[PATCH v4 07/20] powerpc: Convert to GENERIC_CMDLINE

Christophe Leroy
2021-04-02T15:18:08Z

This updates the powerpc code to use the new cmdline building function.

The cmdline_build() defines a temporary string in __initdata.
powerpc uses __prombss instead at the moment, so we must
call cmdline_build() with destination different from the source
to allow GCC to optimise the temporary string out.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
---
v4:
- Use cmdline_build() instead of __cmdline_build()
- Add cmdline_strlcpy() define
---
arch/powerpc/Kconfig | 37 +--------------------------------
arch/powerpc/kernel/prom_init.c | 21 +++++++++----------
2 files changed, 11 insertions(+), 47 deletions(-)

diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index c1344c05226c..6723f10ac246 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -168,6 +168,7 @@ config PPC
select EDAC_SUPPORT
select GENERIC_ATOMIC64 if PPC32
select GENERIC_CLOCKEVENTS_BROADCAST if SMP
+ select GENERIC_CMDLINE
select GENERIC_CMOS_UPDATE
select GENERIC_CPU_AUTOPROBE
select GENERIC_CPU_VULNERABILITIES if PPC_BARRIER_NOSPEC
@@ -888,42 +889,6 @@ config PPC_DENORMALISATION
Add support for handling denormalisation of single precision
values. Useful for bare metal only. If unsure say Y here.

-config CMDLINE
- string "Initial kernel command string"
- default ""
- help
- On some platforms, there is currently no way for the boot loader to
- pass arguments to the kernel. For these platforms, you can supply
- some command-line options at build time by entering them here. In
- most cases you will need to specify the root device here.
-
-choice
- prompt "Kernel command line type" if CMDLINE != ""
- default CMDLINE_FROM_BOOTLOADER
-
-config CMDLINE_FROM_BOOTLOADER
- bool "Use bootloader kernel arguments if available"
- help
- Uses the command-line options passed by the boot loader. If
- the boot loader doesn't provide any, the default kernel command
- string provided in CMDLINE will be used.
-
-config CMDLINE_EXTEND
- bool "Extend bootloader kernel arguments"
- help
- The command-line arguments provided by the boot loader will be
- appended to the default kernel command string.
-
-config CMDLINE_FORCE
- bool "Always use the default kernel command string"
- help
- Always use the default kernel command string, even if the boot
- loader passes other arguments to the kernel.
- This is useful if you cannot or don't want to change the
- command-line options your boot loader passes to the kernel.
-
-endchoice
-
config EXTRA_TARGETS
string "Additional default image types"
help
diff --git a/arch/powerpc/kernel/prom_init.c b/arch/powerpc/kernel/prom_init.c
index 33316ee55265..704afd028213 100644
--- a/arch/powerpc/kernel/prom_init.c
+++ b/arch/powerpc/kernel/prom_init.c
@@ -152,7 +152,7 @@ static struct prom_t __prombss prom;
static unsigned long __prombss prom_entry;

static char __prombss of_stdout_device[256];
-static char __prombss prom_scratch[256];
+static char __prombss prom_scratch[COMMAND_LINE_SIZE];

static unsigned long __prombss dt_header_start;
static unsigned long __prombss dt_struct_start, dt_struct_end;
@@ -770,24 +770,23 @@ static unsigned long prom_memparse(const char *ptr, const char **retptr)
* Early parsing of the command line passed to the kernel, used for
* "mem=x" and the options that affect the iommu
*/
+#define cmdline_strlcat prom_strlcat
+#define cmdline_strlcpy prom_strlcpy
+#include <linux/cmdline.h>
+
static void __init early_cmdline_parse(void)
{
const char *opt;
-
- char *p;
int l = 0;
-
- prom_cmd_line[0] = 0;
- p = prom_cmd_line;
+ bool truncated;

if (!IS_ENABLED(CONFIG_CMDLINE_FORCE) && (long)prom.chosen > 0)
- l = prom_getprop(prom.chosen, "bootargs", p, COMMAND_LINE_SIZE-1);
+ l = prom_getprop(prom.chosen, "bootargs", prom_scratch,
+ COMMAND_LINE_SIZE - 1);

- if (IS_ENABLED(CONFIG_CMDLINE_EXTEND) || l <= 0 || p[0] == '\0')
- prom_strlcat(prom_cmd_line, " " CONFIG_CMDLINE,
- sizeof(prom_cmd_line));
+ truncated = !__cmdline_build(prom_cmd_line, l > 0 ? prom_scratch : NULL);

- prom_printf("command line: %s\n", prom_cmd_line);
+ prom_printf("command line: %s %s\n", prom_cmd_line, truncated ? "[truncated]" : "");

#ifdef CONFIG_PPC64
opt = prom_strstr(prom_cmd_line, "iommu=");
--
2.25.0